The present invention pertains to the field of surgical techniques and relates more particularly to an irrigation and aspiration apparatus which can be used in endoscopic surgery.
It will be recalled that endoscopic surgery and/or exploration generally makes use of irrigation means ensuring the cleaning of the operative site, aspiration means ensuring the removal of liquids and body tissues, and means for dilation or tensioning of the organs or of the cavity on which surgery is being carried out. The irrigation and dilation can be effected simultaneously by injection, under slight pressure, of an isotonic or very slightly hypotonic solution, such as advantageously glycine, on account of its dielectric properties. It will be remembered, as regards this surgical technique, that it is imperative to maintain the excess pressure between a minimum threshold (sufficient to dilate the cavity and to counterbalance the capillary pressure) and a maximum threshold (corresponding to the pressure of absorption of the irrigation liquid by the venous system). These thresholds, which vary between individuals, are approximately 15 and 45 mmHg respectively.
Irrigation techniques have been widely described, particularly in patent publications, and reference may advantageously be made to patents FR 2,244,440 (IGLESIAS), and FR 256,954, FR 2,569,555 (BURNER). The first of these patents describes simple means for supply of irrigation fluid consisting essentially of a gravity reservoir and of valves for controlling the flowrate. The BURNER patents describe more elaborate means, involving in particular the use of means for automatic regulation of the pressure using a pump placed under the control of a pressure regulator. The second of these latter patents describes more particularly an aspiration technique using means for regulating the pressure. However, it will be noted that even apparatuses with controlled pressure do not entirely rule out the risks of liquid passing into the blood system, on account of the significant variations in arterial pressure which can occur during surgery.
Publications WO 8700759 (MINNESOTA), FR 2,378,494 (WOLF) and U.S. Pat. No. 3,900,022 (WIDRAN) also disclose an irrigation device for injecting irrigation liquid into an operative cavity; however, these devices do not comprise means for heating the liquid or controlling its temperature. For related techniques, reference may also be made to the following publications: U.S. Pat. No. 4,486,384 (DARNELL), GB 2,205,244 (BLOGOVESCHENSKY), U.S. Pat. No. 3,177,871 (MYERS) and U.S. Pat. No. 4,702,733 (WRIGHT).
Finally, it is recalled that the haemostatic influence of temperature is well known, but that this influence is the result of two causes with different effects; on the one hand, a cause with a positive effect consisting in an increase in the rate of polymerization of the fibrinogens and the rate of formation of the "platelet clot"; on the other hand, a cause with a negative effect consisting in vasodilation.
As far as the Applicants are aware, no attempt has ever been made, in laparotomy surgery using an irrigation serum, to make use of the haemostatic influence of the temperature of the warm serum alone, because of the predominance of the negative effect; serum at 40.degree.-45.degree. C. has been used in particular, but after pinching or suturing the cut vessels. However, the Applicants considered that it might not be the same in endoscopic surgery on account of the positive effect of putting the operative cavity under excess pressure. Their work thus led them to note that a serum or other irrigation liquid injected at a temperature of between about 42.degree. and 45.degree. C. considerably slowed down the haemorrhagic flow; overall, the use of warm isotonic serum (42.degree.-45.degree. C.) instead of serum at ambient temperature, as in the prior art, has the following results: it accelerates the haemostasis of the vessels spread, permits a reduction in the irrigation flow necessary for cleaning the operative site and for maintaining perfect vision. There still remained the delicate problem of the risks of liquid being transferred into the blood system, with the peri- and post-operative risks which this involves, a problem for which the technique of the invention affords a solution. On the basis of these observations, the invention proposes means ensuring optimal irrigation of the operative site in endoscopic surgery, with a maximum limitation of the risk of the liquid passing into the blood system.